In this study, we use a confocal micro-PIV (Particle Image Velocimetry) system
to investigate red blood cell motions flowing in micro-channels. This system
enables us to visualize the individual RBCs even in the high Hct blood by exciting
the labeled RBCs by the laser. We measure individual trajectories of RBCs in a
micro-channel with stenosis or bifurcation under high Hct conditions. Our results
clearly demonstrate that the trajectories of RBCs strongly depend on the
hematocrit, the RBC property and the position in the micro-channel. This
information is important for a better understanding of mass transport in the
microcirculation.